Just bought a 1984 XL600R

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timstiles · #1 Unread post by **timstiles** » Sun Nov 12, 2006 9:12 pm

Picked this bike up tonight from a guy that says it had a knock in the motor. Are these bikes prone to a certain problem in the engine? It only has 8k miles on it for what its worth. I want to start shopping for a used motor just in case. What year motors would be a exact fit drop in ?

I can't get this damn thing started, it's a b!tch to kick over. I've already ordered the service manual. While I wait for it if anyone has some knowledge of these bikes they want to share I will be reading!

BuzZz · #2 Unread post by **BuzZz** » Mon Nov 13, 2006 7:27 am

Those older XR's are pretty tough. If it really does have a knock in the motor (once you get it running you can hear and trace it better), then you can decide if fixing it is cheaper than a motor swap.

AFAIK you should be able to bolt in any year XR600 motor, the 650's may even fit, but that would require some checking and measureing of the 2 different motors.

If your bike is really hard to kick over, then the most likely cause is a malfunctioning de-compression release. It is an 'automatic' system, tied into the kickstarter. There is a little cable running up to the head/valvetrain area from the engine cases. This cable rusts and sticks or simply breaks. And then kickstarting the bike requires some dedication. The de-comp will allow the kickstarter to start it's travel with little resistance, letting you get a little momentum up before it gets really hard to overcome the engine compression. Without it, you have to get that motor spinning against that comp. from a dead stop at the top of the kickstarter travel. And you know how hard that is.

timstiles · #3 Unread post by **timstiles** » Mon Nov 13, 2006 7:53 pm

What's the small lever under the left grip for ?

I did get it running tonight and it has a loud knock for sure. Aside from previous owner negligence are there any other mechanicals that could have caused this on a bike with only 8k miles?

Tim

CORSCO · #4 Unread post by **CORSCO** » Tue Nov 14, 2006 3:23 pm

Is it a knock or a tick? A knock will be hollow while a tick will be more high pitched. Knock = crankshaft/ Tick = valves or cam chain. A crank gone bad is usually due to lubrication issues, which probably means the previous owner neglected to change his oil. And no, these bikes have no history of problems that I am aware of.
The small lever you mentioned is the decompression lever which was previously mentioned. To start, slowly kick the engine over until resistance is felt, pull the lever in and kick it slightly. When you do not feel as much resistance, kick hard to start.
The decompression lever opens one exhaust valve slightly to relieve compression to aid in starting.

timstiles · #5 Unread post by **timstiles** » Tue Nov 14, 2006 4:28 pm

I wish it were valves ticking. It is definitely a loud knock. So there's a decompression lever on the left grip and some other decompression mechanism tied to the kickstarter? I noticed a spring and cable coming off the kickstarter.

I'm still waiting on the manual I ordered. If theres anyting I can read online regarding engine removal and teardown please send me the links. I know I could do it without the manual but I want to the right way and not break anything in the process!

insaneman_12 · Tue Nov 14, 2006 4:51 pm

Well you need a new motor now because it will cost more to have the motor rebuilt than to replace it. Use the XL if yoiu plan to ride it on the street. Its built for the road. You should be able to find a good running motor at a salvage yard pretty cheap. Make sure you rebuild the carb while replacing the motor. Good luck.

timstiles · #7 Unread post by **timstiles** » Tue Nov 14, 2006 5:20 pm

What motors will work without too much trouble? Only 83-87 XL600/R's ?

Any recommendations for online salvage yards? I'm in northern california, any close by? I went to one in South San Franciso 8 years ago but I forget the name.

BuzZz · #8 Unread post by **BuzZz** » Tue Nov 14, 2006 5:59 pm

I did so forget to remember that some (maybe all) XR-600's had a thumb actuated de-comp lever. I used to Moto with my XR-500 and that lever is the first thing to jab into your thigh when you crank it over and stick your leg out to rail a berm, so I never put mine on. It was gone when I bought the bike used, I saw no need for it at the time. I'm older and lazier now, so I probably wouldn't even try starting one now unless it had one. And I would think long and hard about even trying when so many new bikes have a button to do the whole thing for me.

To damage the engine so badly, the P.O. would almost have to be trying to hurt it. Sure, any mechanical device can fail at any time, but those things are the next toughest thing to a hammer there is. Poor bike....

Time to get friendly with the wreckers and e-bay.

timstiles · #9 Unread post by **timstiles** » Wed Nov 15, 2006 8:27 am

I'm not having much luck even finding used motor dealers in my area. Appreciate any referrals. Is there a place like SBT for jetski motors that does the same for bikes?

insaneman_12 · Wed Nov 15, 2006 3:20 pm

Where are you from. I work at an motorcycle salvage yard in Fresno CA. Any motorcycle salvage yard should be able to locate it. We have a locator program that sends a message to all other salvage yards in the US. They will answer back and ship the motor to the yard.